1. Field of the Invention
This invention relates generally to surface coating and, more particularly, to the low-solvent coating of solid surfaces.
2. Statement of Related Art
Solvent-containing lacquers and paints are mainly used in conventional processes for coating solid surfaces, especially metal and wood surfaces. In an effort to save organic solvents or to avoid them for ecological or safety reasons, water-based lacquers on the one hand and low-solvent and solventless coating systems on the other hand have recently been developed in addition to conventional lacquers and paints. In the field of low-solvent and solventless coating systems, a distinction is drawn between so-called powder lacquers and coatings applied in a liquid form. In powder lacquer technology, curable compounds or preformed thermoplastic polymers are applied to the surface in finely divided form, generally by electrostatic spraying, and are generally cured or melted to form a film by exposure to heat. The systems applied in liquid form are generally reactive compounds of relatively low molecular weight which polymerize on the surface and thus form a solid film.
For coating systems of this type applied in liquid form, only a few of the large number of polymerizable compounds have so far been successful. Polymerizable cyclic iminoethers have not hitherto been proposed as compounds for coating systems of this type. Solventless and low-solvent lacquers based on reactive epoxides, isocyanates, acrylates and melamine resins, some of which give very high-quality coatings, are of importance today. However, they are only used in narrow fields of application because not least their price and certain toxicological objections to some of the reactive components are obstacles to their use on a wide scale. A further explanation of the prior art can be found in the specialist literature, cf. for example Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Vol. 15, Weinheim (1978), pages 590 et seq. and the original literture cited therein.